The invention relates to a machine or accessory for making folded containers, in particular folded boxes, from blanks. The machine has machine elements for acting on and/or moving the blanks or containers which are manually positionable for different blank sizes, position sensors for determining the actual positions of the machine elements to be positioned, and a memory unit for storing the desired positions for various blank sizes.
Folding-box gluing machines of the described type for making folded boxes from blanks have as is known at least the following working stations:
a loader which draws the blanks to be used at high speed from a stack and feeds them individually to the following first working station,
an applicator for adhesive, normally paste, that applies an adhesive strip to the fold tabs to be glued, and
a folding station in which a blank part to be provided with a glue strip for producing a glue joint is bent through 180xc2x0, thus being folded.
Adjacent the folding station there is normally a so-called transfer station in which the boxes are counted, marked, and, if damaged, culled out. Thereafter there is a pressing station at whose intake an overlapping stream of folded blanks is formed which are held in the pressing station for some time under pressure so that the two blank parts of the glue joint are joined. After the folded-box gluing machine there is normally a packing apparatus in which the flat folded boxes are packed in cartons. Furthermore it is standard to provide between the loader and the adhesive applicator a so-called prebreaker in which the folded tabs are folded back and forth so that the corresponding fold lines are made soft by bending through 180xc2x0. Transport of the blanks through the individual working stations or accessories is done by conveyor belts.
In order that the machine can make containers of different shape, the individual stations have machine elements for working on and conveying the blanks that can be positioned for the various blank sizes. Such machine elements to be positioned are for example the stack walls and holding tongues of the loader, the folding elements of the folding station, and the adhesive nozzles or applicator elements of the adhesive applicator, as well as the transport belts in the individual stations or accessories. When made as an accessory the packing apparatus for the folded boxes and a so-called preloader for automatically supplying the loader have elements that must be positioned dependent on blank format. With the exception of the pressing station there are in each working station machine elements that must be repositioned with each change of blank format transversely or longitudinally to the travel direction of the blanks or even vertically.
The product literature xe2x80x9cDIANA 05-3 The Universally Usable Folded Box Gluing Machinexe2x80x9d of applicant describes such a folded box gluing machine that has digital position indicators for the machine elements to be positioned. There is an electronic data book serving as memory unit for the desired positions of the various types of boxes which displays on a screen the desired position to the machine adjuster for manual setting. The folded-box gluing machine is also provided with an adjusting mechanism which is connected to the computer to directly and automatically set the machine elements for format by means of attached drive motors. This system is however very expensive.
The object of the invention is to inexpensively improve a machine or accessory of the described type where the machine elements are manually positioned so that the machine adjuster can manually rapidly set positions with little likelihood of error.
This object is achieved according to the invention in that both the memory unit for the desired positions as well as each position sensor for the respective actual position are connected with a computer which calculates the difference between the respective desired position and the respective actual position, and each machine element to be positioned is associated with a respective display which is connected to the computer and which displays graphically or numerically the difference between the respective actual position and the respective desired position calculated by the computer.
The solution of the invention has the advantage that the machine adjuster when resetting position is shown the amount of repositioning needed to the desired position and preferably also the direction of positioning movement right there where the adjustment must be made. When the difference is equal to zero the desired position has been reached. The adjuster does not need to read the desired position from a remote screen and make a note of it or remember it so that he can set the corresponding machine element to the right position. With the large number of machine elements to be positioned in a folded-box gluing machine the remembering and transferring of desired positions creates the danger of errors and is also time-consuming, e.g. if the adjuster makes a printout of the values.
The solution according to the invention has the further advantage that it contains elements that can all be used when refitting the machine to fully automatic operation.